Copper base alloy



Patented Jan. 17, 1950 COPPER BASE ALLOY T John 1). Berwick, Alton, 111., assignor to Olin in dustries, Inc East Alton, 111., a corporation of Delaware l 9 EN Drawing.

2 Claims.

This invention relates to copper base alloys and more particularly to such an alloy containing as essential constituents, copper, zinc, aluminum, and manganese.

A primary object of this invention is the provision of a relatively inexpensive alloy having strength characteristics, hardness and the like properties comparable to, or improved over, those of the usual aluminum bronzes, but having greatly improved working characteristics and particularly suited as a bearing alloy. The aluminum bronzes employed as a bearing metal heretoforeknown usually contain copper, aluminum and iron, with or without the inclusion of other elements suchas zinc, nickel, lead, tin,

manganese, and silicon. Such alloys require a relatively high annealing temperature between cold working operations in order that such cold working operations may be satisfactorily accomplished. It is therefore, an object of this invention to provide an alloy which may be relatively inexpensively hot or cold worked and which permits relatively low annealing temperatures between cold workin operations and also relatively low temperatures for hot working. Another object is to provide an alloy which can be utilized to provide bearings having low resistance to friction combined with long wearing qualities.

The above and other objects are accomplished in accordance with this invention by the provision of an alloy having a composition within the limits of 80% to 89% copper, 4% to 15.5% zinc, 3.5% to 6.5% aluminum, and 1% to 2.5% manganese. A composition within the above limits containing 85.5% to 88.5% copper, 4% to 6.5% zinc, 5.5% to 6.5% aluminum, and 1.5% to 2.5% manganese is preferred, since this composition has higher strength and hardness with elongation and conductivity substantially equivalent to other compositions within the above limits, thus rendering it especially suited for automotive and aircraft bearings.

It has been found that the inclusion of substantially less than 80% copper in, the alloy results in decreased ductility making cold rolling operations unsatisfactory. The inclusion of less than 3.5% aluminum results in an undesirable decreased strength and hardness, whereas aluminum contents higher than about 6.5% result in casting difliculties and in the precipitation of a delta phase, materially reducing the ductility. More than about 2.5% manganese materially lowers the conductivity whereas less than about 1% manganese results in an undesirable lower strength and hardness. The manganese component contributes greatly to lower the temperature required for annealing after cold working Application October 20, 1945, Serial No. 623,609 1 operations. The zinc component improves the hardness and less than about. 4% zinc makes casting of the alloy diflicult. Minoramounts of impurities such as iron or lead are permissible 5 without destroying the. desirable properties of the alloy. I 7 1 The physical properties of typical compositions exemplifying this invention are shown below in comparison with theproperties of a typical prior 10 aluminum bronze alloy containing iron as an alloying element. Alloys of this invention are designated by the letters A, B, C, D, and E, and the prior alloy is designated by the letter F.

TABLE 1 Composition TABLE 2 Physical properties [After cold rolling to 50% reduction-no subsequent anneal] A B o 1) n F Tensile Strength 1000 1.5.1 118.7 110.0 117.7 112.0 114.0 112.0 Elongation percent in 2inches 2.0 1.0 1.0 1.0 3.0 3.5 Hardness (Rockwell 5 B) 90.5 94.0 94.0 93.0 95.0 95.0

1 Test specimen 0.5 in. wide by 0.020 to 0.080 in. thick.

TABLE 3 Physical properties after annealing A B l 0 D E r Anneal Temp., C 575 575 575 575 650 720 Tensile Strength 1000 p.s.i. 69.0 66.0 67.8 62.2 58.0 67.5 Elongation percent in 2 inches 1 45 41 4s 40 05 42 Hardness (Rockwell B) 61 57 58 49 32 61 l Test specimen 0.5 in. wide by 0.020 to 0.080 in. thick.

50 TABLE 4 Electrical conductivity A B o D E r Conductivity, Percent mos 12.5 11.0 13.0 12.0 11.5 13.0

composition E when annealed at a temperature as high as 650 C. had a tensile strengthmucm lower and a percent elongation much higher than prior composition F whichwas annealed at the temperature of 720 C., thusfurthendemonstrat ing the fact that the alloy of this invention permits a much lower annealing temperature. than such prior alloys. It should also be noted that; the preferred composition containing 85.5% to 88.5% copper, 4% to 6.5% zinc, 5.5% to 615% aluminum, and 1.5% 150.25% manganese, as exemplifiedby composition A, l able 1', has amater-ially higher hardness; Table 2; with elongation and: conductivity; Table 1-; substantially equiv-- alent tothe other-compositions; rendering it especi'ally suitable fonaebearing material. The al- 1037 of this invention, in addition to providing advantages in" cold working operations, likewise permitsitheuse of a lowertemperature forhot working operations than is ordinarily employed with prior aluminumebronzes, which is of decided ad-- vantage; since: aneccnomydn heating is effected and greater-reductions in thickness of metal are permissible between heatingoperations.

Thus, in accordancewithithis invention a novel ductile alloy havinghighstrength and hardness and other properties such as low resistance to 4 friction and grabbing necessary to produce good bearings is provided.

Having thus described the invention, what I claim and desire to secure by Letters Patent is:

1 A coppen-basealloy, susceptiblev to annealing at relatively low temperatures between cold working operations composed of 4% to 15.5% zinc, 3.5% to 6.5% aluminum, 1% to 2.5% manganese-,;and the balance copper, the copper content being 80% to 89%.

21 copper-base ailoy susceptible to annealing at relatively low temperatures between cold working operations composed of 4% to 6.5% zinc, 5.5;%-to.6l5. aluminum, 1.5% to 2.5% manganese, and the balance copper, the copper content being. 85.5% to 88.5%.

JOHN D. BERWICK.

REEEREN (3E8; GI'EED The. following references. are of. record" in the; file of this patent? UNITED STATES; BAiI EN I S-F OTHER. REFERENCES, Aluminum Bronze? 1939 ed., page: 61.

Metals' by Carpenter and Robertson, vol; 2;

1939, pages 1308 and? 1309.- 

1. A COPPER-BASE ALLOY SUSCEPTIBLE TO ANNEALING AT RELATIVELY LOW TEMPERATURES BETWEEN COLD WORKING OPERATIONS COMPOSED OF 4% TO 15.5% ZINC, 3.5% TO 6.5% ALUMINUM, 1% TO 2.5% MANGANESE, AND THE BALANCE COOPER CONTENT BEING 80% TO 89%. 